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All-spectrum oblique transmission through a periodic screen

We show that the all-spectrum transmission blockage through a low-pass screen is bounded by the static polarizability per unit area of the screen, irrespective of how complicated the materials involved are. The angular dependence at oblique incidence is investigated, and the results are verified by measurements on an array of split ring resonators.

Secondary Metabolites from Bolivian Plants- Isolation and Characterization

Popular Abstract in English Plants produce an array of organic chemicals with an enormous diversity of structural types. Many of these phytochemicals are biologically active compounds necessary for the well-being, survival, and evolution of the plants, but also have been used by humans, who have used them in traditional medicine and for pharmaceutical industry. During the course of this research, Nature has been recognized as a rich source of potentially useful chemicals. Throughout the years, phytochemical studies have led to the discovery of an enormous number of natural products, their chemical diversity is unique and many of them possess various biological activities. As a contribution, this thesis presents the results obtained from the phytochemical study of four Bolivian plants. Sene

Plasminogen and protein PAM: Interactions between streptococcal surface proteins and the human fibrinolytic system

Popular Abstract in Swedish Bakgrund Streptococcus pyogenes, eller grupp A streptokocker, är en av de vanligaste sjukdomsframkallande bakterierna hos människan. De orsakar ofta relativt harmlösa och lättbehandlade ytliga infektioner i hals (halsfluss) och hud (svinkoppor) men kan också ge djupare och livshotande infektioner. Dessutom förekommer följdsjukdomar efter infektioner med grupp A streptoPathogenic bacteria often produce potent proteases capable of destroying host tissue thereby providing the bacteria with tools for spreading and nutrient access. This thesis describes how group A, C and G streptococci can acquire surface bound protease activity through an alternative mechanism, namely by binding and activation of the human protease precursor plasminogen. Group A streptococci of c

Joint Under and Over Water Calibration of a Swimmer Tracking System

This paper describes a multi-camera system designed for capture and tracking of swimmers both above and below the surface of a pool. To be able to measure the swimmer's position, the cameras need to be accurately calibrated. Images captured below the surface provide a number of challenges, mainly due to refraction and reflection effects at optical media boundaries. We present practical methods for

Development of the Stress Strategy Test as a personnel selection instrument

Popular Abstract in Swedish Avhandlingen beskriver utvecklingen av ett personlighetstest, Stress Strategy Test (SST), och hur detta test kan skilja på olika personer utifrån personlighet och de särskilda kognitiva strategier de använder sig av. Det relateras också till ett begåvningstest och psykologintervju av över tretusen individer. Testet bygger på den av J.R. Stroop uppmärksammade principenThe thesis concerns the development of a computerised test, termed the Stress Strategy Test (SST), intended for use in a personnel selection and placement context. A similar but less extended form of that test, termed the Stroop Strategy Test, developed first, was adjudged to be somewhat less effective as a selection instrument. Both of the tests, concerned with cognition, personality and ability

The influence of temperature on enzyme selectivity in organic media

Popular Abstract in Swedish Människan har under mycket lång tid använt enzymer vid tillverkning av livsmedel, bland annat vid syrning av mjölk, jäsning av bröd och bryggning av öl och vin. Man använde sig då av hela levande organismer och först på slutet av 1800-talet kunde den aktiva substansen isoleras. Dessa aktiva substanser fick samlingsnamnet enzym, vilket kommer från grekiska och betyder "iThe influence of different reaction parameters on enzyme selectivity was investigated. The reaction conditions studied were solvent dependence, water activity and reaction temperature. The improved selectivity was observed as higher synthetic yields in a-chymotrypsin and subtilisin catalyzed peptide synthesis respectively, and as higher enantioselectivity in the asymmetric reduction of ketones cat